Answer:
7
Step-by-step explanation:
It has a 45 45 90 ratio, so if the hypotenuse is 7 root 2, then the two sides have to be 7.
Given:
The number of seats in the first row is <em>a</em>₁ = 12.
The series of the increasing number of seats is 12, 14, 16......
The objective is to find the total number of seats in the first 12 rows.
Explanation:
The difference between the number of seats in each row can be calculated by the difference between the successive terms of the series.

The number of rows to be calculated is <em>n</em> = 12.
To find the number of seats:
The number of seats presents in the first 12 rows can be calculated as,

On plugging the obtained values in the above equation,

Hence, the total number of seats in the first 12 rows is 276.
Answer:
<em>The population on 30th day will be </em><em>134836</em><em>.</em>
Step-by-step explanation:
This is a case of exponential growth. The general form of exponential function is,

where, a and b are constants.
The data points from the question are 
Putting the values in the function,
for 
----------1
for 
------2
Dividing equation 2 by 1,


Putting the value of b in equation 1,

Now the function becomes,

Putting x=30, we get

Arcsecant or arcsec or sec⁻¹ is an inverse trigonometric function. And many calculators don't have a key for them because they can be calculated with basic trigonometric functions like so:
sec⁻¹(x)=cos⁻¹(1/x).
So the correct answer is the fourth one: y=cos⁻¹(1/x).